Sources close to Kiedis, who has been very public about his struggles with drug addiction, told the New York Daily News he made several visits to Cedars-Sinai Medical Center in Los Angeles this summer.

“Anthony’s health was pretty bleak,” one source told the News. “Organ failure was a possibility. There was talk of how to get him on a transplant list, to cover all the bases, but that opened up a whole new can of worms because people with histories of drug and alcohol abuse are less likely to receive the organs they need.”

Although the singer’s reps have denied reports of poor health and kidney trouble, another friend told the News the treatments had the desired effect and he’s on the mend.

Kiedis’ troubled history will soon get further examination in a new series based on his 2004 memoir, “Scar Tissue,” being developed by HBO.